Railway-traffic-controlling apparatus



Dec.22,1925.. I 1,566,331 I L. V. LEWIS RAILWAY TRAFFIC CONTROLLINGAPPARATUS Filed April 11', 1925 BY (X; X' 1%. 4 6? 7 ATTORNEY PatentedDec. 22, 1925. l

- urtrrE-o STATES PATENT OFFICE.

LLOYD V. LEWIS, OE EDGEWOOD BOROUGH, PENNSYLVANIA, ASSIGNOR To THE UNIONSWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A. CORPORATION OFPENN SYLVLIN'IAJ RAILTVAY-TRAFFICC-CONTROLLING APPARATUS.

Application filed April 11, 1925. Serial No. 22,295.

To all whom it may concern:

Be it known that I, LLOYD V. LEWIS, a citizen of the United States,residing at Ed ewood Borough, in the county of Alleg eny and State ofPennsylvania, haveinvented certain nev and useful Improvements inRailway-Traflic-Controlling Apparatus, of which the following is aspecification.

My invention relates-to railway traffic controllingapparatus, andparticularly to apparatus of the type comprising governing means carriedon a train and controlled by alternating current received from thetrackway.

One feature of my invention is the provision in apparatus" of thisnature of means for controlling an induction motor relay by a singlephase source of current received from the track.

' I will describe one form of apparatus embodying my invention, and wilthen point out the novel features thereof in claims.

The accompanying drawing is a diagraminatic view showing one form ofapparatus embodying my invention.

Referrin to the drawing, the reference characters and 1 designate thetrack rails of aj railway along which trailic normally 3 moves in thedirection indicated by the arrow. These rails-are divided by insulatedjoints 2 into aplurality of track sections, of which only onecomplete-section C -D is shown in the drawing. Each'section is pro videdwith a track circuit comprising a track battery 3 and a track relay R.The rails of each section are also supplied with alternating traincontrolling current under the control of trafiic conditions in advanceof the section. As here shown, this latter current is furnished byinterposing between the track battery 3 and one rail 1, the secondary 4of a transformer E, the primary 5 of which is at times supplied withalternating train controlling current from the secondary 7 of atransformer F. The primary 8 of each transformer F. is constantlyconnected with asource of alternating current which is not shown in thedrawing. The circuit for the primary 5 of each transformer E ineludes afront contact 6 of the track relay R for the track section next in adya0e, '50 that a ternati g rain controlling current issupplied to therails of a section when the section next in advance is unoccupied butnot when such section next in advanceie occupied. I

As shown in the drawing, section CD is occupied b a train'W. Located inadvance of the orward wheels and axle of this train are a pair of cores9 and 9 disposed above the two rails J1 and 1 respectively, which corescarry windingslO and -1O respectively'. The windings 10 and 10 areconnected in a pick-up circuit G in such manner that the alternatingcurrents induced in these winding by train controlling current in thetrack rails are additive. The pick-up circuit G includes a condenser 11,and this condenser, together with the two windings 10 and 10", arepreferably'tuned to resonance at the frequency of the train controllingcurrent.

The train governing apparatus includes a relay H of the induction motortype, comprising two stator windings 26 and 27, and a rotor 30 whichoperates a contact 31. The supply of current to the stator winding 26 ofrelay H is controlled by the voltage across condenserll, through themedium of a two-' stage amplifier comprising tubes X and X The supplyof'current to the other stator winding 27 of relay H is similarlycontrolled by thevoltage across condenser 11,-through the medium of atwo-stage amplifier 'comprising amplifier tubes Y and Y In a traincontrol system of the type to which t1 1e present invention relates, aninduction motor relay is preferable to a direct current relay, becauseof the fact that the induction motor relay is immune to shock andvibration, and has desirable selec: tive frequency characteristics. Theinduction motor relay operates efliciently only when it is supplied withtwo-phase energy. 95 It is, of course, possible to energize an inductionmotor relay from a single phase Source. by incorporat' phase splittingdc: vices within the. relay, ut such devices are. necessarilyineflicient and increase the total power consumed by the relay to apoint be yond the output available from an ordinary vacuum tubeamplifier. It is also possible to operate an induction motor relayefficiently by providing a separate two-stage 105 amplifier for eachphase, butwhen n e o t is made to split the phases in the inputciramplifier circuits is that the output circuit cuits to saidamplifiers difiiculty is encountered due to loss of efiiciency becauseof the extremely minute energy available in the pick-up circuit G. In myinvention I eliminate these difiiculties by providing a two-stageamplifier for each winding of the induction motor relay andincorporating a phase-splitting device between the first and second '0stages of one amplifier.

As illustrated in the drawing, the filaments 12 of the four amplifiertubes are connected in series, together with limiting resistances and19, across a filament bat- 15 tery A. The voltage across condenser 11'in the pick-up circuit G is impressed across the grid and filament ofthe amplifiertube X. The grid 13 of this tube is maintained at a fixednegative direct current potential with 29 respect tothe filament 12 ofthe same tube by an'amount'equal to the drop in potential due to thefilament current flowing in resistance 15. That is to say, grid 13 oftube X is connected directly with one terminal of condenser 11., andfilament 12 of this tube is connected with the other terminal ofcondenser 11 through the resistance 15. With the grid 13 thusmade'negative with respect to the filament, oscillations can bemaintained in the input circuit of tube X without loss of energy byconduction from grid 13.

Amplifier tube X is provided-with a plate circuit which includes a platebattery 13 having one terminal connected with the plate 14 of tube Xthrough a reactance 24, and the other terminal connected with thefilament circuit at point 32. The .am lified voltagevariations in thisplate circu t appear as a variation in potential between the plate 14and the filament 12 of tube X, which potential is impressed through acon denser 17 across the grid and filament of tube X. The function ofcondenser 17 is to block the positive battery potential from the grid oftube X'. The grid of tube X is provided with a negative bias by beingconnected through a id leak resistance 18 to the filament circuit atpoints 33 which is negative with respect to the negative end of thefilament 12 of tube X the amount of negative bias in this instance beingrepresented by the drop across the resistance 19 and the filament 12 oftube Y.

Y The ube X is provided with a plate circuit which includes the platebattery B and the stator winding 26 of relay H. X. The amplifiercircuits associated with the other. winding 27 of relay H differ from 9those fassociated with winding 26 in two parc na s. The grid of tube Ywould have a j-eXcessive negative bias if it were coniiected directly tocondenser 11, and, consequently, a blocking condenser 16 is interposed.The other difference between the proper adjustment of reactance 22.

condenser-s 2.8 and 29 respectively.

for tube Y contains the phase shifting means.

The plate circuit for tube Y includes the plate batteryB and a reactance25. The output circuit for tube Y passes from plate 14 of this tube,through a condenser 20, a second condenser 21, and a reactance 22 to thefilament 12 of tube Y. I will first assume for purposes of discussionthat condenser 21 is omitted. The output circuit comprising condenser 20and reactance 22 are tuned. to resonance at the frequency of thealternating train controlling current, and, so a voltage will be builtup across reactance 22 which is greater in amplitude than tlre yyoltageacross the plate and filament of tube Y and is'approximately inquadrature relation to the latter voltage. This voltage across reactance22 is impressed across the grid and filament of tube Y To accomplishthis, a high resistance 23 is connected across the terminals ofreactance 22 (the actual circuit including condenser 21). The grid 13 oftube Y is connected adjustably with any desired point on resistance 23,and the filament 12 of tube Y is connected with reactance 22, throughfilament 12 of tube X and resistance 19. This arrangement provides aready means for adjusting the voltage impressed upon the grid andfilament of tube Y by properly choosing the -point at which the grid 13is connected with resistance 23, and this adjustment will not disturbthe phase of the voltage impressed across the grid and filament of tubeY As pointed out hereinbefore, the voltage Will be approximately inquadrature relation to the corresponding voltage impressed upon the gridand filament of tube X The negative bias of the grid of tube Y isobtained by a blocking condenser 21', but it is necessarythat the gridcircuit for tube Y include a high resistance as itis in multiple withthe iiput circuit of this tube. Inasmuch as resistance 23 and reactance22 may be of low resistance to direct current, I interpose the blockingcondenser 21 between the condenser 20 and the reactance 22. The capacityof the blocking condenser 21 should be about ten times as great as thatof condenser 20, so that it will have but slight efi'ect upon theresonance between condenser 20 and reactance 22. and may in effect becompensated for by the The plate circuit or tube Y includes winding 27of relay H. It Will be evident. therefore, that the currents supplied tothe two relay windings26 and 27 will be approximately in quadrature, sothat the operation of this relay is efiicient.

Each winding 26 and 27 of relay H is preferably tuned to resonance atthe frequency of the train controlling current by Although I have hereinshown and re,

two-stage amplifier interposed between said circuit and the otherwinding of said relay and means located between the two stages of one ofsaid amplifiers t'or displacing the phase of the current supplied to theassociated. relay winding with respect to the phase of the currentsupplied to the other relay wi riding.

2. Train carried apparatus con'iprising a piclcup circuit receivingalternating current from the tracit'way, an induction motor relay. aMontage amplifier interposed between said circuit and one winding: ofsaid Iii) relay. a twostage amplifier interposed be-.

tween said circuit and the other winding of said relay, and meansassociated withthe input circuit the second stage of one of saidamplifiers for displacing the phase of the current supplied to theassociated relaywinding with respect to the phase of the currentsupplied to the other relay winding".

3. Train carried apparatus comprising' a pick-up circuit rcceiyincalternating current ll'Oli') the traclnvay, an induction inotorrclay,

a two-stage amplifier interposed between said circuit and one winding ofsaid relay. a two-stage aiuphlier interposed between said circuit andthe other winding of said relay and means for tuning the output cir cuitof the first stage of one of said amplifiers to resonance at thefrequency of said alternating current for displaciiig" the phase of thecurrent supplied to the associated relay winding with respect to thephase of the current supplied to the other relay windin".

4. Train carried apparatus comprising a pick-up circuitreceivingalternating current from the trackway, an induction motor relay, a two-stage amplifier interposed between said circuit and onewinding of said relay, a two-stage amplifier interposed between saidcircuit and" the other Winding of said relay. the output circuit of thefirst/"stage of one of said amplifiers containing a condenser and areactance tuned to resonance at the frequency of said alternatingcurrent, a resistance connected across said react-ance, and the inputcircuit for the second stage of the same amplifier beingconnected acrossone terminal of said reactance and a point on said resistance. v 1

Train carried apparatus comprisinga piclcup circuit receivingalternating current from the trackway. an induction motor relay, atwo-stage amplifier interposed between said circuitand one winding ofsaid relay, a

twostage amplifier interposed between said circuit and the other Windingof said relay, the output circuit of the first. stage of one ofsaid'amplifiers containing two condensers 20 and 21 and a reactance 22connected in series and tuned substantially to resonance at thefrequency of said alternating current, a resistance 23 connected acrossthat part of the resonant circuit which includes condenser 21 andreactance 2 2, the grid of the second stage of the same amplifier beingconnected with a point on said resistance and the lilament of the saidsecond stage of the same vamplifier being connected with said reactancethrough the filament of the second stage of the other amplifier and aresistance 19.

In testimony whereof I affix my signature.

LLOYD V. LEWVIS.

